broken shared build.

[pawels@…]

hi,

i'm using a boost with a custom namespace (e.g. bcp --namespace=foobar --namespace-alias ...). for such configuration the current version of program_options doesn't export symbols from shared library.

afaics the current boost build system defines in such configuration -DFOOBAR_PROGRAM_OPTIONS_DYN_LINK=1 macro which doesn't match the boost/program_options/config.hpp:37 #ifdef:

#if defined(BOOST_ALL_DYN_LINK)

defined(BOOST_PROGRAM_OPTIONS_DYN_LINK)

finally, the BOOST_PROGRAM_OPTIONS_DECL macro is empty.

this is a regression from boost-1.64.0.